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authorPablo Neira Ayuso <pablo@netfilter.org>2009-02-05 23:56:36 -0800
committerDavid S. Miller <davem@davemloft.net>2009-02-05 23:56:36 -0800
commitff491a7334acfd74e515c896632e37e401f52676 (patch)
tree0e3663706a706029d6fc749ef7f66cdd03925231 /lib/kobject_uevent.c
parent612e244c12215f6f74973ea3b89bff96450dc530 (diff)
downloadlinux-ff491a7334acfd74e515c896632e37e401f52676.tar.gz
netlink: change return-value logic of netlink_broadcast()
Currently, netlink_broadcast() reports errors to the caller if no messages at all were delivered: 1) If, at least, one message has been delivered correctly, returns 0. 2) Otherwise, if no messages at all were delivered due to skb_clone() failure, return -ENOBUFS. 3) Otherwise, if there are no listeners, return -ESRCH. With this patch, the caller knows if the delivery of any of the messages to the listeners have failed: 1) If it fails to deliver any message (for whatever reason), return -ENOBUFS. 2) Otherwise, if all messages were delivered OK, returns 0. 3) Otherwise, if no listeners, return -ESRCH. In the current ctnetlink code and in Netfilter in general, we can add reliable logging and connection tracking event delivery by dropping the packets whose events were not successfully delivered over Netlink. Of course, this option would be settable via /proc as this approach reduces performance (in terms of filtered connections per seconds by a stateful firewall) but providing reliable logging and event delivery (for conntrackd) in return. This patch also changes some clients of netlink_broadcast() that may report ENOBUFS errors via printk. This error handling is not of any help. Instead, the userspace daemons that are listening to those netlink messages should resync themselves with the kernel-side if they hit ENOBUFS. BTW, netlink_broadcast() clients include those that call cn_netlink_send(), nlmsg_multicast() and genlmsg_multicast() since they internally call netlink_broadcast() and return its error value. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib/kobject_uevent.c')
-rw-r--r--lib/kobject_uevent.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index 318328ddbd1..38131028d16 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -227,6 +227,9 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
NETLINK_CB(skb).dst_group = 1;
retval = netlink_broadcast(uevent_sock, skb, 0, 1,
GFP_KERNEL);
+ /* ENOBUFS should be handled in userspace */
+ if (retval == -ENOBUFS)
+ retval = 0;
} else
retval = -ENOMEM;
}